1. Field of the Invention
The present invention relates to a microfilm reader-printer, and particularly to a microfilm reader-printer operative in a printing mode to select a copy paper of an optimum size.
2. Description of the Prior Art
Conventional microfilm reader-printers are designed to print a magnified microfilm image, which is projected on the screen, in the same size on a copy paper, and the screen is dimensioned slightly larger than the largest copy paper used by the microfilm reader-printer. For example, when the copy papers has sizes of B5, A4 and B4, the screen has dimensions slightly larger than the B4 size.
In such a microfilm reader-printer operating with a variety of sizes of the copy paper, however, frequently used paper sizes in practice are intermediate sizes (e.g., A4 size), and the use of larger-sized copy paper (e.g., B4 size) is less frequent. The same is true on smaller-sized copy paper.
The conventional microfilm reader-printers are designed to deal with the largest paper size irrespective of the actual frequency of demand, resulting in a bulky apparatus with a high screen position which involves a problem of operability.
To cope with this matter, there is proposed a more compact microfilm reader-printer with a reduced screen size through the provision of a conversion lens in the optical reader system for projecting a microfilm image on the screen so that the projected image on the screen is smaller than the image printed on the cop paper, as described in Japanese Patent Application Laid-open No. Sho 55-9582. However, the apparatus of this design operates to project images of various sizes on the screen through the reduction in a constant size ratio with respect to the printed images, and therefore it is degraded as a reader in the performance of image resolution.